An inkjet printer is widely used because it has several advantages including a fast print speed, a low cost, and high-resolution image display. In an inkjet recording system, small ink droplets are ejected onto a paper, etc. from one or more nozzles to create characters or images.
Various types of recording sheets, including such as a specially coated sheet of print paper and a print film as well as plain paper, are used for an inkjet printer. Recently, improvement in image quality for an inkjet recording sheet has been rapidly attempted. In particular, with the widespread of digital cameras, image quality comparable to a photographic image and similar texture quality to real photo paper have been required.
Korean Patent No. 10-435294 discloses a recording sheet of paper for inkjet printer in which an additive containing as a main component a cationic resin made by reacting at least secondary amine, ammonia, epihalohydrin, and a crosslinking agent is applied on a surface of or in a sheet of paper. However, such resin coated paper has disadvantages of curling after printing, paper jamming and poor image quality upon continuous printing.
To overcome the problems, there was developed a recording sheet including a hydrophobic support film made of cellulose acetate or polyester such as polyethylene terephthalate and a microporous layer (referred to as “ink absorbing layer”, hereinafter) made of inorganic particles and a hydrophilic polymer on the support film. For example, Korean Patent Laid-Open Publication No. 2004-22720 discloses a recording medium for inkjet printer, in which an ink absorbing layer including a binder, a filler, and an ionomer is formed on a surface of a support film selected from a polyester film, a polycarbonate film, and a cellulose acetate film. However, the support film has low stiffness, and thus, the recording medium has a texture different from real photo paper. Further, adhesion between the support film and the ink absorbing layer is poor, and thus, delamination of the ink absorbing layer from the support film may occur.
In this regard, the above patent publication also discloses that an undercoating layer may be selectively formed between the support film and the ink absorbing layer. However, enhancement in adhesion between the ink absorbing layer and the support film is insufficient. Also, in a case where the undercoating layer and the support film are different in elongation, surface cracks may be caused.
Meanwhile, in order to impart a texture to a photo image and to achieve non-glossy coating, a technique of attaching separate matte paper treated with elaborate embossing finish or matte finish to a surface of a recording sheet has been attempted. However, an additional processing step is required to attach matte paper to a surface of a recording sheet, resulting in an increase of a manufacturing cost and degradation of processing efficiency. Further, the use of separate matte paper may deteriorate image quality.